When glycolic acid was introduced in the early 1990s, it was revolutionary for skin care. Known as an alpha hydroxy acid (AHA), it was the first over-the-counter active ingredient you could use at home to accelerate dead-skin-cell sloughing and reveal the fresher, smoother, plumper skin underneath.
https://www.shape.com/lifestyle/beauty-style/skin-benefits-lactic-malic-phytic-tartaric-citric-acid
https://www.shape.com/lifestyle/beauty-style/skin-benefits-lactic-malic-phytic-tartaric-citric-acid